Compact L-series telephoto lens with an Image Stabilizer which compensates for camera shake with equivalent effect of a shutter speed two stops faster. Two Image Stabilizer modes are provided: Stabilizer Mode 1 (the same mode featured on the EF 75-300mm f/4-5.6 IS USM) and the new Stabilizer Mode 2 which steadies the image during horizontal or vertical panning.
The image stabilizer also functions when using the Extender EF1.4xII or Extender EF2xII to provide that elusive 600mm shooting capability.

Focal length and maximum aperture: 300 mm 1:4
Lens construction: 15 elements in 11 groups
Diagonal angle of view: 8°15'
Focus adjustment: Rear focusing system with USM
Closest focusing distance: 1.5m / 4.9ft
Filter size: 77mm